This invention relates generally to a portable fan device and, more particularly, to a portable fan device with an improved demountable protective grill assembly.
Many environmental conditioning devices utilize fan blades to produce air movement. Typically, such devices include protective grills that permit substantially unimpeded air flow while preventing potentially injurious physical contact with the fan blades employed. For ease of manufacturing, shipping and storage, protective grills often are discrete assemblies removably attachable to the operating unit.
Prior detachable grill assemblies have exhibited individually and collectively a variety of disadvantages. For example, certain types of connectors such as preassembled rivoted hinges and closure rings are not easily replaceable after breakage thereby rendering unsafe the units on which they are used. Other devices have protective grills attached with clips that require specially designed tools for removal. Still other securing elements are either costly to manufacture or cumbersome to assemble.
U.S. Pat. No. 5,073,088 discloses an improved attachment system for a removable protective grill. Fastening elements included in the disclosed attachment system alleviate the problems described above. However, under certain conditions, the fastening elements can produce undesirable noise resulting from vibration.
The object of this invention is to provide for a fan device a noise free attachment system for a removable protective grill.